Surgical Arm And Method Of Providing Visual Guidance For Operating Same

ABSTRACT

A surgical arm is presented. The surgical arm comprises a first interface configured to receive a device for performing or assisting a surgical procedure and multiple adjustment members configured to adjust the surgical arm relative to a respective adjustment axis. The surgical arm further comprises at least two operating members configured to operate different ones of the adjustment members, wherein the operating members are marked with different visual codings. Further a method for providing visual guidance for operating the surgical arm according to a pre-determined surgical approach is presented.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of copending U.S. application Ser.No. 16/739,786, filed Jan. 10, 2020, the entire contents of which arehereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to assisted surgery. In particular, asurgical arm adjustable relative to multiple adjustment axes ispresented. Also presented is a method of providing visual guidance foroperating the surgical arm. The present disclosure can be implemented asa surgical arm, a method, a computer program product and a system.

BACKGROUND

Computer assisted surgery has made considerable progress in recentyears, for example to plan and visualize a surgical approach for asurgeon to reach a surgical target inside a patient's body. To assistthe surgeon in properly operating a surgical tool, such as a drill or abiopsy needle, in accordance with the planned surgical approach, asurgical arm may be used. The surgical arm is adjustable relative tomultiple adjustment axes and, once properly adjusted in accordance withthe planned surgical approach, permits an exact guidance of the surgicaltool to the surgical target.

It will be appreciated that a proper adjustment of the surgical arm isof utmost importance for an optimal surgical result. At the same time,the adjustment has to be performed as quickly as possible to shorten theduration of the surgical procedure and the resulting stress on thepatient.

SUMMARY

There is a need for a surgical arm that can be adjusted quickly and inan exact manner. Also, there is a need for providing visual guidance forefficiently operating such a surgical arm.

According to one aspect, a surgical arm is presented, the surgical armcomprising a first interface configured to receive a device forperforming or assisting a surgical procedure and also comprisingmultiple adjustment members configured to adjust the surgical armrelative to a respective adjustment axis. The surgical arm furthercomprises at least two operating members configured to operate differentones of the adjustment members, wherein the operating members are markedwith different visual codings.

The surgical arm may be a mechanical element configured to be usedduring a surgical procedure (e.g., in a sterile operating room). Thesurgical arm may be used by a surgeon for placing and/or aligning asurgical tool or any other device (e.g., a guidance member for thesurgical tool). In one example, the surgical arm may be used forproperly orienting a biopsy needle or other surgical tool. As such, thefirst interface may be configured to receive a guidance device such as aneedle sleeve shaped to receive the biopsy needle, or such as a drillsleeve.

The adjustment members may be mechanical components, for examplegearwheels, toothed racks or (ball) joints. The adjustment members maybe configured to move at least one moveable part of the surgical armalong and/or around a specific axis.

Each particular adjustment axis may be a rotational or a translationalaxis. In case of a rotational adjustment axis, the surgical arm may beconfigured to be moved around this axis. In case of a translationalaxis, the surgical arm may be configured to be moved along this axis.For example, the surgical arm may comprise two rotational adjustmentaxes and two translational adjustment axes. In another example, thesurgical arm may only comprise one rotational adjustment axis and onetranslational adjustment axis. The respective rotational andtranslational adjustment axes may be perpendicular to one another.

The operating members may be manually or electrically (e.g., by anelectric motor) operable. Each of the operating members may beconfigured such that by operating the operating member, the surgical armwill be moved around a specific rotational adjustment axis or along aspecific translational adjustment axis associated with the operatingmember. In one example, one or more of the operating members may berotatable elements, such that rotating the operating members in a firstrotation direction causes the surgical arm to be moved in a firstadjustment direction relative to a specific adjustment axis associatedwith the operating member. When rotating the operating member in asecond rotation direction different from (e.g., opposite to) the firstrotation direction, the surgical arm may be moved in a second adjustmentdirection different from (e.g., opposite to) the first adjustmentdirection relative to the specific adjustment axis. In other examples,the operating members may be slidable elements (e.g., levers) orpushable elements (e.g., buttons).

The visual codings may be cognitively detectable by a human observer(e.g., a user such as a surgeon) and/or electrically detectable by anelectronic component (e.g., a camera of a surgical navigation system).Different visual codings may be clearly distinguishable from one anotherby the human observer as well as the electronic component. In oneexample, the visual codings may be different colors. In another example,the visual codings may be different visual patterns, e.g., differentgeometric forms. In yet another example, the visual codings may bedifferent shadings, e.g., dashed and/or dotted lines.

The surgical arm may further comprise at least two locking membersassociated with different ones of the operating members. The lockingmembers may be manually or electrically (e.g., by an electric motor)operable. Each of the locking members may be configured to lock the armin position with respect to a specific movement relative to therespective adjustment axis of the associated operating member. Like theoperating members, the locking members may also be rotational, slidableand/or pushable elements. When one of the locking members is operated tobe active (i.e., locking), the surgical arm may no longer be adjustablerelative to the specific adjustment axis of the associated operatingmember. In other words, in a locked state, the locking member may fixthe surgical arm with respect to a specific movement (e.g., rotatory ortranslatory) relative to a specific alignment axis.

In some variants, the locking members may respectively be coded with thesame visual coding as the operating member associated with therespective adjustment axis. The respective visual codings of a lockingmember and an associated operating member may be identical. For example,if a specific operating member associated with a respective adjustmentaxis is encoded with a blue color, the locking member associated withthe specific operating member may also be encoded with a blue color. Inanother example, if a specific operating member is encoded with a dottedpattern, the locking member associated with said operating member mayalso be encoded with the dotted pattern.

In some implementations, the operating members as well as the lockingmembers may be configured rotatably. As described above, rotating theoperating member in a first rotation direction may cause the surgicalarm to be adjusted in a first adjustment direction. Likewise, rotatingthe locking member in a first direction may fix an alignment of thesurgical arm relative to a specific alignment axis. Additionally,rotating the locking member in a second direction different from thefirst direction may enable further alignment of the surgical armrelative to the specific alignment axis. The operating members and thelocking members may for example be represented by rotatable turningknobs or pivotably mounted levers.

At least a first one of the adjustment members may be configured toadjust the surgical arm along a translational adjustment axis. At leasta second one of the adjustment members may be configured to adjust thesurgical arm around a rotational adjustment axis. In one variant, aspecific adjustment member may be associated with a specific adjustmentaxis. Alternatively, two or more adjustment members may be associatedwith the same adjustment axis. In the latter variant, a first adjustmentmember may be configured to adjust the surgical arm in one direction(e.g., a positive x-direction) and a second adjustment member may beconfigured to adjust the surgical arm in a second direction (e.g., anegative x-direction).

In some variants, the surgical arm may comprise a second interface forreceiving a tracking device configured to be tracked by a surgicalnavigation system. The tracking device may for example be an opticaltracking device such as a reflective marker. Additionally, or in thealternative, the surgical arm may comprise the tracking deviceconfigured to be tracked by a surgical navigation system.

As said, the different visual codings may be different colors. Oneoperating member and the locking members associated with that operatingmember may be encoded in yellow, and a different operating memberassociated with a different locking member may be encoded in blue.

In some embodiments, the surgical arm may further comprise a guidancedevice coupled to the first interface. The guidance device may define anoperative axis and may be configured to guide a surgical tool along theoperative axis. The guidance device may be configured to be received by(e.g., to be coupled to) the first interface.

According to a second aspect, a method of providing visual guidance foroperating a surgical arm according to a pre-determined surgical approachis provided. The surgical arm comprises a first interface configured toreceive a device for performing or assisting a surgical procedure andmultiple adjustment members configured to adjust the surgical armrelative to a respective adjustment axis. The surgical arm furthercomprises at least two operating members configured to operate differentones of the adjustment members, wherein the operating members are markedwith different visual codings. The method comprises the steps ofdetermining at least one of a current position and a current orientationof the first interface or a device received by the first interface, anddetermining, based on the pre-determined surgical approach, at least oneof a target position and a target orientation of the interface or thedevice. The method further comprises the step of, based on a differencebetween at least one of the current and target positions and the currentand target orientations, determining that an adjustment of the surgicalarm is required relative to at least one adjustment axis; and triggeringa display of the visual coding associated with the at least oneoperating member associated with the at least one adjustment axis so asto provide visual guidance.

The steps may be performed by a processing unit of a computer system(e.g., as part of a surgical navigation system). The processing unit maytrigger a display unit (e.g., a monitor) of the computer system toprovide the visual guidance.

The pre-determined surgical approach may be a planned trajectory of asurgical tool for reaching an area within a patient's body where asurgical procedure is to be performed. For example, the pre-determinedsurgical approach may correspond to the planned trajectory of a biopsyneedle that is to be entered into the skull of a patient. Thepre-determined surgical approach may be pre-operatively planned using acomputer system, such as a surgical navigation system.

The planned trajectory may comprise a starting point (e.g., an entrypoint into the body) according to the pre-determined surgical approach.Alternatively or additionally, the planned trajectory may comprise anendpoint (e.g., an anatomical target) according to the pre-determinedsurgical approach.

In some variants, the visual guidance may comprise a display of thevisual coding in combination with an indication of a direction in whichthe associated operating member is to be operated. For example, if thevisual codings are different colors and the operating members areconfigured rotatably, visual guidance may be provided by displaying acolor coding of a specific operating member together with the image ofan arrow depicting a direction in which the rotatable operating memberis to be rotated.

The visual guidance may further comprise a display of the visual codingin combination with an indication of an amount by which the associatedoperating member is to be operated. The indication of an amount by whichthe associated operating member is to be operated may be in the form ofa first number of geometric elements (and/or a first geometric form suchas a circle having a first size) in association with the visual codingof the operating member. For example, the operating members may berotatably mounted and the indication could be represented by a number ofsegments of a circle representative of a number of degrees by which aspecific operating member has to be turned.

The method may further comprise displaying a second number of geometricelements (and/or a second geometric form such as a circle having asecond size different form the first size) in association with a visualcoding different than the visual coding of the first number of geometricelements (and/or the first geometric form), the second number ofgeometric elements (or the second geometric form) being indicative of anamount by which the associated operating member has been operated. Inthe above described example, a first number of segments of a circle maybe filled with a visual coding associated with the respective operatingmember and a second number of segments of the circle may be filled witha visual coding different from the visual coding associated with therespective operating member.

In some variants, the method may further comprise determining a specificadjustment axis relative to which the surgical arm deviates the mostamong all adjustment axes from the pre-determined surgical approach. Inthis case the method may further comprise prioritising the provision ofvisual guidance for said specific adjustment axis over any otheradjustment axis.

The method may further comprise the step of trigger a display of anumerical value indicative of an amount by which a specific adjustmentaxis deviates from the pre-determined surgical approach. The method mayfurther comprise triggering a display of a superposition of at least oneof the current position and the current orientation of the firstinterface or a device received in the first interface relative to thepre-determined surgical approach.

In some implementations, the at least one of a current position and acurrent orientation of the first interface or the device received by thefirst interface may be determined by tracking, using a surgicalnavigation system, a tracking device that is in a fixed spatialrelationship with at least one of the first interface and the devicereceived by the first interface.

According to a further aspect, a computer program product is presented,the computer program product comprising computer program instructions toperform the method steps of the above described method when executed bya processor.

According to a further aspect, a system comprising the surgical arm asdescribed above and the above described computer program product ispresented.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, advantages and aspects of the present disclosure willbecome apparent from the following embodiments taken in conjunction withthe drawings, wherein:

FIG. 1 shows a perspective view of an embodiment of a surgical arm;

FIG. 2A shows a perspective view of the surgical arm of FIG. 1 , whereina guidance device with an attached tracking device has been removed fromthe surgical arm;

FIG. 2B shows an exploded view of the surgical arm of FIG. 2A;

FIGS. 3A-3B illustrate enlarged views of different portions of thesurgical arm of FIG. 1 ;

FIG. 4 shows a flow diagram of a method embodiment of providing visualguidance for operating a surgical arm according to a pre-determinedsurgical approach;

FIG. 5 shows different representations of visual guidance for operatinga surgical arm according to a pre-determined surgical approach; and

FIGS. 6A-6D show a temporal sequence of visual guidance based on avisual coding and in combination with an indication of a direction inwhich an associated operating member is to be operated.

DETAILED DESCRIPTION

In the following description, exemplary embodiments of a surgical armand a technique of providing visual guidance for operating the surgicalarm will be explained with reference to the drawings. The same referencenumerals will be used to denote the same structural features.

FIGS. 1, 2A and 2B show an embodiment of a surgical arm 10 that isconfigured to be used during a surgical procedure. The surgical arm 10is intended to be attached to a support frame (not shown) that isfixedly positioned in an operating room relative to a patient. As anexample, the surgical arm 10 may be attached via the support frame to anoperating table or an operating chair. In some variants, the surgicalarm 10 is used for computer-assisted neuro-surgery, for example to guidea surgical tool towards a surgical target (e.g., a tumor) within thepatient's skull.

The surgical arm 10 comprises an interface 12 configured to receive adevice for performing or assisting the surgical procedure. In thepresent embodiment, the device interface 12 is configured as a sleevewith a cylindrical through-hole. It will be apparent to one skilled inthe art that the device interface 12 could also be configured in adifferent manner, for example as a rail.

The device to be received by the device interface 12 can be a surgicaltool or can be configured to cooperate with (e.g., to guide) a surgicaltool. In the exemplary embodiment of FIGS. 1, 2A and 2B, the deviceinterface 12 is configured to receive a guidance device 14 for a biopsyneedle, a surgical drill or other any surgical tool. The guidance device14 is concentrically received within the sleeve-like device interface 12and defines an operative axis 16. In the present embodiment, theguidance device 14 has a cylindrical through-hole configured to guidethe surgical tool along the operative axis 16 towards the surgicaltarget within the patient. It will be appreciated that in otherembodiments, the guidance device 14 could be realized as a guide rail orotherwise.

The arm 10 comprises a further interface 18 configured to receive atracking device 20 that is to be tracked by a surgical navigationsystem. In the present embodiment, the tracking device 20 is an opticaltracking device and comprises four reflective spheres that are locatedspaced apart from each other at the end of four respective arms. Ofcourse, the tracking device 20 could also be configured to compriseactive light sources or other trackable elements. Moreover, the trackingdevice 18 could also be integrally formed with a component of thesurgical arm 10, such as the guidance device 14 or the device interface12.

In the present embodiment, the tracker interface 18 is part of theguidance device 14, which in turn is detachably mounted in the deviceinterface 12 (see FIGS. 1 and 2A). In other embodiments, the trackerinterface 18 is mounted to the device interface 12 or another componentof the surgical arm 10 with a fixed relationship to the device interface12.

As shown in the exploded view of FIG. 2B, the surgical arm 10 comprisesfour adjustment members 22, 24, 26 and 28 configured to adjust thesurgical arm 10 relative to different adjustment axes 30, 32 and 34. Theadjustment members 22, 24, 26 and 28 are operated by operating members36, 38, 40 and 42. In the present embodiment, the operating members 36,38, 40 and 42 are configured rotatably, i.e., as turning knobs. However,the present disclosure is not limited thereto. For example, one or moreof the operating members 36, 38, 40 and 42 could also be configured fortranslatory movement (e.g., as slidable and/or pushable elements).Moreover, one or more of the operating members 36, 38, 40 and 42 couldbe configured to be electrically operable by an electric motor (notshown).

In the present embodiment, each of the operating members 36, 38, 40 and42 is configured to operate exactly one of the adjustment members 22,24, 26 and 28. Operating one or more of the operating members 36, 38, 40and 42 serves to adjust the surgical arm 10 relative to at least oneadjustment axis 30, 32 and 34. More specifically, as illustrated in FIG.1 , operating the operating member 36 translatorily moves the surgicalarm 10 along adjustment axis 32 in two opposite directions according todouble-headed arrow 44. Likewise, operating the operating member 38translatorily moves the surgical arm 10 along adjustment axis 30 in twoopposite directions according to double headed arrow 46. The twoadjustment axes 30, 32 extend perpendicular to each other.

On the other hand, operating member 40 is configured to rotationallymove the surgical arm 10 around adjustment axis 30 in two oppositedirections according to double headed arrow 48. Further, operatingmember 42 is configured to rotationally move the surgical arm 10 aroundadjustment axis 34 in two opposite directions according to double headedarrow 50.

As is clear from the above description, operating member 38 andoperating member 40 are configured to adjust the surgical arm 10relative to adjustment axis 30 in a translatory and in a rotatorymanner, respectively. Adjustment member 24 is configured to adjust thesurgical arm 10 along adjustment axis 30 and adjustment member 26 isconfigured to adjust the surgical arm 10 around adjustment axis 30. Inan alternative embodiment, adjustment axis 32 and adjustment axis 34 maycoincide. In this or another embodiment, operating member 38 andoperating member 42 may be configured to adjust the surgical arm 10relative to different adjustment axes.

Each of the operating members 36, 38, 40 and 42 is marked with adifferent visual coding. The different visual codings can easily bedistinguished by a human operator of the surgical arm 10 withoutsignificant cognitive effort.

In the drawings, each of the operating members 36, 38, 40 and 42 isexemplarily marked with a different geometric pattern. In particular,operating member 36 is marked with a pattern in the form of a grid.Further, operating member 38 is marked with a pattern in the form ofdots. Operating member 40 is marked with a pattern in the form ofstraight lines. Operating member 42 is marked with a pattern in the formof black and white diamonds. It is to be understood that the visualcodings in the form of geometric patterns of the operating members 36,38, 40 and 42 only serve as an illustrative example and are not limitedthereto. In another example, the operating members 36, 38, 40 and 42 maybe marked with visual codings in the form of different colors (e.g.,red, green, yellow and blue, respectively).

The surgical arm 10 depicted in FIGS. 1, 2A and 2B further compriseslocking members 52, 54, 56 and 58. Locking member 58 is not visible inFIG. 1 , but is shown in FIG. 2B. Each of the locking members 52, 54, 56and 58 is associated with exactly one of the operating members 36, 38,40 and 42. That is, locking member 52 is associated with operatingmember 36, locking member 54 is associated with operating member 38,locking member 56 is associated with operating member 40 and lockingmember 58 is associated with operating member 42. The associationbetween the locking members 52, 54, 56 and 58 and the respectiveoperating members 36, 38, 40 and 42 is depicted in the drawings by thefact that each of the locking members 52, 54 and 56 is marked with thesame visual coding (i.e., the same geometric pattern) as its associatedoperating member 36, 38, 40 and 42. In more detail, locking member 52 ismarked with the grid pattern of operating member 36, locking member 54is marked with the dot pattern of operating member 38, locking member 56is marked with the line pattern of operating member 40 and lockingmember 58 is marked with the black and white diamond pattern ofoperating member 42. Reference is made to the respectively marked ringsencircling the locking symbols of the locking members 52, 54 and 56 inFIGS. 1 to 3B. The visual codings of the operating members 36, 38, 40and 42 and the respective locking members 52, 54, 56 and 58 will bedescribed in more detail with reference to FIGS. 3A and 3B below.

The locking members 52, 54, 56 and 58 are configured to lock thesurgical arm 10 in position relative to a dedicated movement relative tothe respective adjustment axis 30, 32, 34 of an associated operatingmember 36, 38, 40 and 42. That is, after the surgical arm 10 hasproperly been aligned relative to the patient with respect to each oneof the adjustment axes 30, 32 and 34 using the operating members 36, 38,40 and 42, the associated locking member 52, 54, 56 and 58 is operatedsuch that the corresponding alignment of the surgical arm 10 can nolonger be changed.

In the embodiment of FIG. 1 , the locking members 52, 54, 56 and 58 areconfigured rotatably, i.e., in the form of rotatable levers. The lockingmembers 52, 54, 56 and 58 may have a definite locking position. Forexample, rotating the locking members 52, 54, 56 and 58 clockwise by 90°may lock the surgical arm 10 in position relative to a dedicatedmovement with respect to the associated adjustment axis 30, 32 or 34associated with the respective locking member 52, 54, 56 and 58.Further, rotating any of the locking members 52, 54, 56 and 58counterclockwise by 90° may unlock the position of the surgical arm 10,i.e., the surgical arm may again be moveable relative to the associatedadjustment axis 30, 32 and 34.

FIG. 2A shows the surgical arm 10 according to FIG. 1 in a partlydisassembled configuration. In more detail, the guidance device 14 isremoved from the device interface 12. As shown in FIG. 2A, the trackerinterface 18 for detachably receiving the tracking device 20 is attachedto the guidance device 14. As stated above, the surgical arm 10 can beoperated with a variety of different surgical tools (e.g., a biopsyneedle or a surgical drill). Depending on the specific surgical tool, adifferent guidance device 14, configured to receive the surgical tool,may have to be inserted into the first interface 12. As the trackerinterface 18 is attached to the guidance device 14, a positionalrelationship between the tracking device 20 and the guidance device 14can remain fixed and can be defined in advance, which simplifies thetracking process of for example a spatial orientation of the guidancedevice 14 (and, thus, of any surgical tool guided therein).

FIG. 2B shows an exploded view of the surgical arm 10 of FIG. 1 . Thefour adjustment members 22, 24, 26 and 28 are clearly visible.

As can be seen in FIG. 2B, the adjustment members 22 and 24 comprisescrew threads 60, 62 configured to adjust the surgical arm 10 uponrotation of the adjustment members 22 and 24 (via the associatedoperating member 36, 38) in a translational manner along the associatedadjustment axis 30, 32 (not depicted in FIG. 2B). Further, theadjustment member 26 comprises a groove 63 accommodating a sphericalfront end of a shaft 64 of the operating member 40. The shaft 64comprises a thread cooperating with a complementary thread in a bore ofa stationary member 65. By turning the operating member 40, the shaft 64moves towards or away from adjustment member 26 that is tiltablerelative to the adjustment axis 30. As the spherical head of the shaft64 is movably captured within the groove 63 of the adjustment member 26,a movement of the shaft 64 towards or away from the adjustment member 26tilts, or rotates, the latter relative to adjustment axis 30.

In a similar manner as operating member 40, also operating member 42comprises a threaded shaft 66 with a spherical head. The thread of shaft66 cooperates with a complementary thread in a bore of adjustment member26. By turning operating member 42, shaft 66 moves towards or away fromadjustment member 28 that is tiltable relative to the adjustment axis 34(not depicted in FIG. 2B). As the spherical head of the shaft 66 iscaptured within a groove 67 of the adjustment member 28, a movement ofthe shaft 66 relative to the adjustment member 28 tilts, or rotates, thelatter relative to the adjustment axis 34.

As can also be gathered from FIG. 2B, the surgical arm 10 furthercomprises an attachment interface 68 configured to attach the surgicalarm 10 to a support frame (not shown). The support frame, in turn, maybe attached to an operating table or an operating chair.

FIG. 3A shows a top view of a portion of the surgical arm 10, comprisingthe operating member 36 and the locking member 52 associated therewith.FIG. 3B, on the other hand, shows a front portion of the surgical arm10, comprising the operating member 40 and the locking member 56associated therewith. As can be seen in FIGS. 3A and 3B, each of thelocking members 52, 56 is marked with the same visual codings as itsassociated operating member 36, 40. In particular, locking member 52 ismarked with the same grid pattern 70 as its associated operating member36. Further, locking member 56 is marked with the same line pattern 72as its associated operating member 40. Therefore, it is immediatelyapparent to the user (e.g., a surgeon) that operating member 36 andlocking member 52 pertain to the same adjustment axis 32. The same holdstrue for operating member 40 and locking member 56.

Furthermore, the different visual codings of the operating members andthe associated locking members are also detectable by a camera, such asa camera of a surgical navigation system (e.g., the same camera that isalso used to track the tracking device 20). Thus, also a processing unitof the surgical navigation system can determine each association betweenone of the visually coded operating members and one of the visuallycoded locking members. Moreover, an association between each visuallycoded operating member and the respective adjustment axis associatedtherewith can be known to the processing unit a priori (e.g., can bepre-stored in a storage medium). Consequently, the surgical navigationsystem can easily determine which operating member to operate in orderto adjust the surgical arm 10 relative to a specific adjustment axis.Further, the surgical navigation system can determine which lockingmember to operate in order to lock the surgical arm 10 in positionrelative to a respective adjustment axis. The surgical navigation systemmay also be able to display said associations to a user in order toprovide visual guidance for aligning the surgical arm 10, or to performthe alignment automatically (e.g., via electric motors).

The interaction between the user, such as the surgeon, and the surgicalnavigation system in order to provide visual guidance for operating thesurgical arm 10 is now described in further detail with reference toFIGS. 4, 5 and 6A to 6D.

FIG. 4 shows a flow diagram 400 of an exemplary method of providingvisual guidance for operating a surgical arm (e.g., the surgical arm 10)according to a pre-determined surgical approach.

The pre-determined surgical approach may be defined by at least one of asurgical target (e.g., in the form of a point or an extended object suchas a tumor) located within a patient's body and an entry point where asurgical tool will enter the patient's body. In some variants, thesurgical approach is defined by a trajectory that connects a planned (oractual) entry point at a body surface of the patient with a plannedtarget. The pre-determined surgical approach may be defined by thesurgeon pre-operatively using a computer system and previously generatedpatient images.

The method starts in step S01 with determining at least one of a currentposition and a current orientation of at least one of the deviceinterface 12 and a device (e.g., guidance device 14 or a surgical toolaccommodated therein) received by the device interface 12. Determiningthe current position and/or orientation may be performed using asurgical navigation system tracking the tracking device 20 within agiven coordinate system. As described with reference to FIG. 2A, apositional relationship between the tracking device 20 and the guidancedevice 14 of the surgical arm 10 may be known a priori (e.g., because itis fixed). In an operating state of the surgical arm 10, the guidancedevice 14 will be coupled to the device interface 12. As such, thetracking device 20 will be in a fixed spatial relationship to the deviceinterface 12 and the guidance device 14 received therein (and, ofcourse, in a fixed spatial orientation to a surgical tool guided by theguidance device 14). Thus, in the embodiment of FIG. 2A, the currentposition and orientation of the first interface 12 and the guidancedevice 14 can easily be tracked by the surgical navigation system.

The method continues in step S02 with determining at least one of atarget position and a target orientation of the device interface 12 orthe guidance device 14. The target position and/or orientation will bedetermined based on the pre-determined surgical approach. As an example,the target position and target orientation of the device interface 12 orthe guidance device 14 may be defined to be concentrically aligned witha linear trajectory connecting the planned or actual entry point (e.g.,in the patient's skull) with the surgical target (e.g., a brain tumor).

If a difference between the current and target positions and/or currentand target orientations is detected (e.g., by the surgical navigationsystem), it is determined in step S03 that an adjustment of the surgicalarm 10 is required relative to at least one adjustment axis (e.g.,adjustment axis 30, 32 or 34). The difference may for example be givenby a distance (e.g., in millimeters) by which a position of the surgicalarm 10 deviates in a certain direction from the pre-determined surgicalapproach. Alternatively or additionally, the difference may also begiven by an angle (e.g., in degrees) by which an orientation of thesurgical arm 10 deviates from the pre-determined surgical approach.

If an adjustment according to step S03 is required, the navigationsystem (e.g., a processing unit thereof) triggers the display of visualguidance for a user in order to properly adjust a position and/ororientation of the surgical arm 10 in accordance with the pre-determinedsurgical approach. Visual guidance may be provided by displaying on adisplay device a visual coding associated with the at least oneoperating member 36, 38, 40, 42 that is associated with the at least oneadjustment axis 30, 32, 34 relative to which the surgical arm 10deviates from the pre-determined surgical approach.

The provision of visual guidance will be explained in the following inmore detail with reference to FIGS. 5 and 6A to 6D.

FIG. 5 shows an exemplary display of a display device, such as a monitorof the surgical navigation system. The display provides visual guidancefor operating the surgical arm 10 according to the pre-determinedsurgical approach and based on the visually coded operating members 36,38, 40 and 42.

In FIG. 5 , a pre-determined surgical approach for reaching a braintumor is depicted. A planned entry point on a patient's skull isindicated by a circle 74 and a planned target location defined by thetumor is indicated by a cross 76. The corresponding surgical approachdefines a planned trajectory of a surgical tool (e.g. a biopsy needle).This trajectory is represented by a straight line 78 connecting theentry point 74 and the target location 76.

In FIG. 5 , three different views of the pre-determined surgicalapproach are shown relative to a pre-operative or intra-operative imageof the patient's skull. In the top left view of the exemplary display ofFIG. 5 , a cross-sectional front view of the patient's skull isdisplayed together with a view of the patient's brain 80 and thepre-determined surgical approach 74, 76, 78. In the top right view ofthe exemplary display of FIG. 5 , a cross-sectional side view of thepatient's skull is shown together with a view of the brain 80 and thepre-determined surgical approach 74, 76, 78. In other words, the viewaccording to the top right illustration is rotated by 90° with respectto the view according to the top left illustration. In the bottom leftillustration of the exemplary display of FIG. 5 , a view perpendicularto the pre-determined surgical approach 74, 76, 78 is shown, i.e., theactual view a surgeon would see before entering a surgical instrumentinside the patient's skull. The images of the patient's skull and brain80 in the top row of the exemplary display of FIG. 5 may be obtained by3D Computer Tomography (CT) imaging or using Magnetic Resonance Imaging(MRI).

In the bottom right view of FIG. 5 , visual guidance for operating thesurgical arm 10 according to the pre-determined surgical approach isprovided. In more detail, a schematic representation 82 of the surgicalarm 10 is shown. The schematic representation 82 of the surgical arm 10is further accompanied by checkmarks 84, 86. Each of the checkmark 84,86 is associated with a dedicated movement relative to one of theadjustment axes 30, 32, 34 by operating one of the four operatingmembers 36, 38, 40, 42 and indicates that the surgical arm 10 is alreadyaligned with respect to at least one of the adjustment axes 30, 32, 34and the planned surgical trajectory 78 (for adjustment axis 30, only thetranslational movement is completed, whereas a rotational movement isstill needed for proper alignment).

Further, the computer system provides the user with informationregarding a specific operating member 36, 38, 40 and 42 associated witha specific adjustment axis 30, 32, 34 to be operated for properalignment of the surgical arm 10 (i.e., of the device interface 12and/or the guidance device 14) according to the pre-determined surgicalapproach. In the embodiment of FIG. 5 , the user is provided with visualinformation relating to the operating member 40 that is associated withthe adjustment axis 30. The information comprises a numerical value 88indicative of an amount by which the alignment of the surgical arm 10deviates from the pre-determined surgical approach 74, 76, 78 relativeto the adjustment axis 34.

The deviation of the alignment of the surgical arm 10 from thepre-determined surgical approach relative to each of the adjustment axes30, 32, 34 may exemplarily be calculated as follows. The pre-determinedsurgical approach 74, 76, 78 may be planned and registered in thecoordinate system of a surgical navigation system, e.g., based on imagedata of a surgical imaging method such as CT or MRI.

Further, the position of the tracking device 20 received in the secondinterface 18 may be tracked by a tracking component of the surgicalnavigation system, such as a camera. As the tracking device 20 isarranged in a known spatial relationship to a surgical tool received inthe first interface 12, the position and/or orientation of the surgicaltool (i.e., the actual trajectory of the tool) may be derived based onthe known spatial relationship. Said position and/or orientation of thesurgical tool may then also be registered into the coordinate system ofthe surgical navigation system. The angles between the pre-determinedsurgical approach 74, 76, 78 and the position and/or orientation of thesurgical tool received in the first interface 12 may then be calculatedin at least two dimensions, based on the above determinations. As such,the angular distances between the pre-determined surgical approach 74,76, 78 and the actual trajectory of the surgical tool may be known withrespect to every adjustment axis 30, 32, 34.

Further, the visual information comprises an indication of which of theoperating members 36, 38, 40 and 42 a user has to turn in order tocompensate the misalignment associated with the numerical value 88. Inthe embodiment of FIG. 5 , the operating members 36, 38, 40 and 42 arenot visually coded with geometric patterns as in FIGS. 1 to 3C, but arevisually coded with different colors. It will be appreciated that bothtypes of visual codings are interchangeable and can also be combined. Inthe present case, operating member 40 is marked with a blue color andconfigured as a turning knob (see FIG. 1 ). Therefore, a user isinformed by a text message that the blue knob is to be turned (seereference numeral 90). Visual guidance in regard to an amount 92 bywhich the operating member 40 is to be turned and a direction 94 inwhich the operating member 40 is to be turned is further provided to theuser. In the embodiment of FIG. 5 , the amount 92 by which the operatingmember 40 is to be turned is represented by a number of color-codedrectangles 93. The rectangles 93 are coded with the same color as therespective turning knob 40 (i.e., blue). A direction 94 in which theturning knob 40 is to be turned is represented by an arrow, indicating acounterclockwise rotation in the embodiment of FIG. 5 . It is to beunderstood that the above-described visual guidance only servesillustrative purposes and is in no way intended to limit the scope ofthe present disclosure.

The visual guidance regarding a specific operating member associatedwith a specific adjustment axis as provided to a user will now bedescribed in more detail with respect to FIGS. 6A to 6D. In particular,an exemplary alignment process of the surgical arm 10 relative to theadjustment axis 30 (rotatory alignment) associated with the operatingmember 40 is shown in several steps indicative of a temporal sequence.It will be apparent that similar guidance will be provided for atranslator alignment in regard to the axis 30 and for alignment relativeto the remaining axes 32, 34, but using other colors (e.g., red, yellowand green).

FIG. 6A shows the beginning of the alignment process of the surgical arm10 around adjustment axis 30. As already shown in the bottom right viewof FIG. 5 , the user is provided with the schematic representation 82 ofthe surgical arm 10, as well as the checkmarks 84, 86 indicating thatthe surgical arm 10 is already aligned with respect to translationalmovements along adjustment axes 30 and 32. Additionally, the user isalso provided with visual guidance 90 as to the operating member that isto be turned, visual guidance 92 as to the amount by which the operatingmember is to be turned, and visual guidance 94 as to the direction theoperating member is to be turned. Specifically, the visual guidance 92as to the amount the operating member is to be turned is represented bya number of color-coded rectangles 93. In FIG. 6A, three color-codedrectangles 93 are displayed. This display indicates that the operatingmember marked in blue is to be turned in the direction indicated byarrow 94 (i.e., in counterclockwise direction) by four entire turns(three color-coded rectangles 93 and the color-coded head of arrow 94).Alternatively, the number of color-coded rectangles 93 may indicate aspecific amount of degrees (e.g., in steps of 10° or more) by which aparticular operating member is to be turned. For example, onecolor-coded rectangle 93 may be indicative of turning the blue operatingmember by 90° in the direction indicated by arrow 94. Alternatively, onecolor-coded rectangle 93 may be indicative of turning the blue operatingmember by 10° in the direction indicated by arrow 94. In the case wherethe color-coded rectangles 93 are indicative of an amount of degrees bywhich the operating members are to be turned, a user may be informed(e.g., haptically) if the operating member has been turned by thespecified amount of degrees. For example, the user may be informed thatthe blue operating member has been rotated 90° in a counterclockwisedirection by providing a small mechanical resistance every 90°. Thus,the user may need to apply a slightly greater force to overcome themechanical resistance in order to rotate the turning knob further.

The required number of turns by which a specific operating member is tobe turned may exemplarily be calculated as follows. Each of theoperating members 36, 38, 40 and 42 may be provided with a thread memberfor operating the respective adjustment member 22, 24, 26 and 28. Thethread members may have known thread pitches. For example, the operatingmembers 36 and 38 configured to operate the adjustment members 22 and24, respectively, may be turning knobs and may have a pitch of 2 mm.Turning the turning knobs 36 or 38 for an entire turn (i.e., 360°) maythus for example cause the biopsy arm 10—and hence also a surgical toolreceived inside the first interface 14—to move along the respectiveadjustment axes 30 or 32 by 2 mm. Depending on the dimensions of themechanical components of the surgical arm 10, moving the surgical arm 10by 2 mm along an adjustment axis may correspond to a rotation of thesurgical tool by 2.25°. In a further example, the operating members 40and 42 configured to operate the adjustment members 26 and 28,respectively, may also be turning knobs and may have a pitch of 0.75 mm.Turning the turning knobs 40 or 42 for an entire turn (i.e., 360° maythus for example cause the biopsy arm 10—and hence also a surgical toolreceived inside the first interface 14—to rotate around the respectiveadjustment axes 30 or 34 by 1.75°, depending on the dimensions of themechanical components of the surgical arm 10. These known relationsbetween an amount of turns of the operating members 36, 38, 40 and 42configured as turning knobs and a rotation of the surgical tool relativeto a specific adjustment axis 30, 32 and 34 may be transformed by thecomputer system into the visual guidance 92 as to the amount arespective operating member is to be turned.

FIG. 6B shows a first intermediate state of the alignment process of thesurgical arm 10 around adjustment axis 30 according to a pre-determinedsurgical approach. As illustrated in FIG. 6B, the blue operating memberhas already been rotated by an amount corresponding to two color-codedrectangles 93. For example, the blue operating member has been rotatedby two entire turns or alternatively has been rotated by 180°, oralternatively has been rotated by 20°.

FIG. 6C shows a later intermediate state of the alignment process of thesurgical arm 10 around adjustment axis 30. Here, the blue operatingmember has already been rotated by an amount corresponding to threecolor-coded rectangles 93. For example, the blue operating member hasbeen rotated by three entire turns or alternatively has been rotated by270°, or alternatively has been rotated by 30°.

FIG. 6D shows the final state of the alignment process of the surgicalarm 10 around the adjustment axis 30. Here, the surgical arm 10 isproperly aligned in accordance with the pre-determined surgical approachwith respect to all possible movements relative to all adjustment axes30, 32, 34. Therefore, each of the corresponding operating members 36,38, 40 and 42 associated with the respective adjustment axes 30, 32 and34 is provided with a checkmark 84, 86, 96, 98. Hence, when alloperating members 36, 38, 40 and 42 are provided with checkmarks asdepicted in FIG. 6D, the user may conclude that the alignment process ofthe surgical arm 10 according to the pre-determined surgical approachhas ended. In the next step, a surgical procedure may now be performed.

When the adjustment process is completed for a dedicated movementrelative to a particular adjustment axis, i.e., when one of thecheckmarks 84, 86, 96, 98 is displayed, the user will secure thisadjustment by operating the associated locking member 52, 54, 56, 58. Insome variants, a text message is displayed in this case to explicitlyrequest the user to do so.

In the above embodiments, a surgical arm 10 comprising visually codedoperating members 36, 38, 40 and 42 as well as a method of providingvisual guidance for operating the surgical arm 10 have been presented.As has become apparent from the embodiments, the visual coding of theoperating members 36, 38, 40, 42 facilitates the identification of aspecific operating member 36, 38, 40, 42 by a user. Therefore, thealignment process of the surgical arm 10 can be made faster uponproviding proper visual guidance.

In some variants, locking members 52, 54, 56, 58 are associated with theoperating members 36, 38, 40 and 42 and are coded with the same visualcoding as the associated operating member 36, 38, 40 and 42. Hence, theuser easily identifies a specific locking member 52, 54, 56, 58associated with the operating member 36, 38, 40, 42 the user iscurrently operating or wishes to operate next. This further speeds upthe alignment process and at the same time increases user convenience.Moreover, as the association between an individual operating member 36,38, 40, 42 and the respective locking member 52, 54, 56, 58 isimmediately apparent to the user due to the same visual coding, the riskthat the user operates a wrong operating member 36, 38, 40, 42 and/orlocking member 52, 54, 56, 58 such that the surgical arm 10 is notcorrectly aligned (e.g., brought out of previously establishedalignment) is reduced.

Additionally, the different visual codings of the operating members 36,38, 40, 42 are also perceivable and distinguishable by an electroniccomponent, e.g., a camera. As such, a computer system attached to thecamera (e.g., a surgical navigation system) can easily determine thespecific operating member 36, 38, 40, 42 that is currently operated andwhich operating member 36, 38, 40, 42 should be operated next accordingto a pre-determined surgical approach. The computer system can transferthis information to a user aligning the surgical arm 10 in an easy anddefinite way by simply providing the user with the respective visualcoding of said operating member 36, 38, 40, 42. Thus, there is no needfor the user to first transform (possibly erroneously) the informationreceived from the computer system into corresponding operation steps.Consequently, user convenience is further improved and at the same timethe failure rate in the alignment process of the surgical arm 10 islowered.

1. A method of providing visual guidance for operating a surgical armaccording to a pre-determined surgical approach, the surgical armcomprising a first interface configured to receive a device forperforming or assisting a surgical procedure, multiple adjustmentmembers configured to adjust the surgical arm relative to a respectiveadjustment axis, and at least two operating members configured tooperate different ones of the adjustment members, wherein the operatingmembers are marked with different visual codings, the method comprisingthe steps of: determining at least one of a current position and acurrent orientation of the first interface or a device received by thefirst interface; determining, based on the pre-determined surgicalapproach, at least one of a target position and a target orientation ofthe interface or the device; based on a difference between at least oneof the current and target positions and the current and targetorientations, determining that an adjustment of the surgical arm isrequired relative to at least one adjustment axis; and triggering adisplay of the visual coding associated with the at least one operatingmember associated with the at least one adjustment axis so as to providevisual guidance, wherein the visual guidance comprises the display ofthe visual coding in combination with an indication of an amount bywhich the associated operating member is to be operated.
 2. The methodaccording to claim 1, wherein the visual guidance comprises a display ofthe visual coding in combination with an indication of a direction inwhich the associated operating member is to be operated.
 3. The methodaccording to claim 1, wherein the indication of an amount by which theassociated operating member is to be operated is in a form of at leastone of a first number of geometric elements and a first geometric formin association with the visual coding of the operating member.
 4. Themethod according to claim 3, further comprising displaying at least oneof a second number of geometric elements and a second geometric form inassociation with a visual coding different than the visual coding of thefirst number of geometric elements and the first geometric form,respectively, the second number of geometric elements or the secondgeometric form being indicative of an amount by which the associatedoperating member has been operated.
 5. The method according to claim 1,further comprising: determining a specific adjustment axis relative towhich the surgical arm deviates the most among all adjustment axes fromthe pre-determined surgical approach; and prioritizing the provision ofvisual guidance for said specific adjustment axis over any otheradjustment axis.
 6. The method according to claim 1, further comprisingtriggering a display of a numerical value indicative of an amount bywhich a specific adjustment axis deviates from the pre-determinedsurgical approach.
 7. The method according to claim 1, furthercomprising triggering a display of a superposition of at least one ofthe current position and the current orientation of the first interfaceor a device received in the first interface relative to thepre-determined surgical approach.
 8. The method according to claim 1,wherein the at least one of a current position and a current orientationof the first interface or the device received by the first interface isdetermined by tracking, using a surgical navigation system, a trackingdevice that is in a fixed spatial relationship with at least one of thefirst interface and the device received by the first interface.
 9. Asystem comprising: a surgical arm comprising: a first interfaceconfigured to receive a device for performing or assisting a surgicalprocedure; multiple adjustment members configured to adjust the surgicalarm relative to a respective adjustment axis; and at least two operatingmembers configured to operate different ones of the adjustment members,wherein the operating members are marked with different visual codings;and a computer program product comprising computer program instructionsconfigured to be executed by a processor to cause the processor toperform a method of providing visual guidance for operating the surgicalarm according to a pre-determined surgical approach in which theprocessor is configured to: determine at least one of a current positionand a current orientation of the first interface or a device received bythe first interface; determine, based on the pre-determined surgicalapproach, at least one of a target position and a target orientation ofthe interface or the device; based on a difference between at least oneof the current and target positions and the current and targetorientations, determining that an adjustment of the surgical arm isrequired relative to at least one adjustment axis; and triggerdisplaying the visual coding associated with the at least one operatingmember associated with the at least one adjustment axis so as to providevisual guidance, wherein the visual guidance comprises the displaying ofthe visual coding in combination with an indication of an amount bywhich the associated operating member is to be operated.
 10. The systemaccording to claim 9, wherein the visual guidance comprises a display ofthe visual coding in combination with an indication of a direction inwhich the associated operating member is to be operated.
 11. The systemaccording to claim 9, wherein the indication of an amount by which theassociated operating member is to be operated is in a form of at leastone of a first number of geometric elements and a first geometric formin association with the visual coding of the operating member.
 12. Thesystem according to claim 11, wherein the processor is furtherconfigured to trigger displaying of at least one of a second number ofgeometric elements and a second geometric form in association with avisual coding different than the visual coding of the first number ofgeometric elements and the first geometric form, respectively, thesecond number of geometric elements or the second geometric form beingindicative of an amount by which the associated operating member hasbeen operated.
 13. The system according to claim 9, wherein theprocessor is further configured to: determine a specific adjustment axisrelative to which the surgical arm deviates the most among alladjustment axes from the pre-determined surgical approach; andprioritize the provision of visual guidance for said specific adjustmentaxis over any other adjustment axis.
 14. The system according to claim9, wherein the processor is further configured to trigger displaying ofa numerical value indicative of an amount by which a specific adjustmentaxis deviates from the pre-determined surgical approach.
 15. The systemaccording to claim 9, wherein the processor is further configured totrigger displaying of a superposition of at least one of the currentposition and the current orientation of the first interface or a devicereceived in the first interface relative to the pre-determined surgicalapproach.
 16. The system according to claim 10, wherein the at least oneof a current position and a current orientation of the first interfaceor the device received by the first interface is determined by tracking,using a surgical navigation system, a tracking device that is in a fixedspatial relationship with at least one of the first interface and thedevice received by the first interface.
 17. A computer program productcomprising computer program instructions, when executed on a processor,are configured to perform the steps of: determining at least one of acurrent position and a current orientation of a first interface or adevice received by the first interface; determining, based on apre-determined surgical approach, at least one of a target position anda target orientation of the first interface or the device; based on adifference between at least one of the current and target positions andthe current and target orientations, determining that an adjustment of asurgical arm is required relative to at least one adjustment axis; andtriggering a display of a visual coding associated with the at least oneoperating member associated with the at least one adjustment axis so asto provide visual guidance, wherein the visual guidance comprises thedisplay of the visual coding in combination with an indication of anamount by which the associated operating member is to be operated. 18.The computer program product according to claim 17, wherein the visualguidance comprises a display of the visual coding in combination with anindication of a direction in which the associated operating member is tobe operated.
 19. The computer program product according to claim 18,wherein the indication of an amount by which the associated operatingmember is to be operated is in a form of at least one of a first numberof geometric elements and a first geometric form in association with thevisual coding of the operating member.
 20. The computer program productaccording to claim 18, wherein the computer program product is furtherconfigured to trigger displaying at least one of a second number ofgeometric elements and a second geometric form in association with avisual coding different than the visual coding of the first number ofgeometric elements and the first geometric form, respectively, thesecond number of geometric elements or the second geometric form beingindicative of an amount by which the associated operating member hasbeen operated.